coresight: tmc: Explicit type conversions to prevent integer overflow

Perf cs_etm session executed unexpectedly when AUX buffer > 1G.

  perf record -C 0 -m ,2G -e cs_etm// -- <workload>
  [ perf record: Captured and wrote 2.615 MB perf.data ]

Perf only collect about 2M perf data rather than 2G. This is becasuse
the operation, "nr_pages << PAGE_SHIFT", in coresight tmc driver, will
overflow when nr_pages >= 0x80000(correspond to 1G AUX buffer). The
overflow cause buffer allocation to fail, and TMC driver will alloc
minimal buffer size(1M). You can just get about 2M perf data(1M AUX
buffer + perf data header) at least.

Explicit convert nr_pages to 64 bit to avoid overflow.

Fixes: 22f429f19c41 ("coresight: etm-perf: Add support for ETR backend")
Fixes: 99443ea19e8b ("coresight: Add generic TMC sg table framework")
Fixes: 2e499bbc1a92 ("coresight: tmc: implementing TMC-ETF AUX space API")
Signed-off-by: Ruidong Tian <tianruidong@linux.alibaba.com>
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230804081514.120171-2-tianruidong@linux.alibaba.com

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index 79d8c64eac4947385741345337335d42d238014c..7406b65e2cdda86d22118c52ef98c50b02d1fdcc 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -452,7 +452,7 @@ static int tmc_set_etf_buffer(struct coresight_device *csdev,
                return -EINVAL;
 
        /* wrap head around to the amount of space we have */
-       head = handle->head & ((buf->nr_pages << PAGE_SHIFT) - 1);
+       head = handle->head & (((unsigned long)buf->nr_pages << PAGE_SHIFT) - 1);
 
        /* find the page to write to */
        buf->cur = head / PAGE_SIZE;

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 766325de0e29bdb0b83a332a1195149eadc284c1..66dc5f97a009804f739a1baf0bfa043395b4ea6f 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -45,7 +45,8 @@ struct etr_perf_buffer {
 };
 
 /* Convert the perf index to an offset within the ETR buffer */
-#define PERF_IDX2OFF(idx, buf) ((idx) % ((buf)->nr_pages << PAGE_SHIFT))
+#define PERF_IDX2OFF(idx, buf)         \
+               ((idx) % ((unsigned long)(buf)->nr_pages << PAGE_SHIFT))
 
 /* Lower limit for ETR hardware buffer */
 #define TMC_ETR_PERF_MIN_BUF_SIZE      SZ_1M
@@ -1267,7 +1268,7 @@ alloc_etr_buf(struct tmc_drvdata *drvdata, struct perf_event *event,
         * than the size requested via sysfs.
         */
        if ((nr_pages << PAGE_SHIFT) > drvdata->size) {
-               etr_buf = tmc_alloc_etr_buf(drvdata, (nr_pages << PAGE_SHIFT),
+               etr_buf = tmc_alloc_etr_buf(drvdata, ((ssize_t)nr_pages << PAGE_SHIFT),
                                            0, node, NULL);
                if (!IS_ERR(etr_buf))
                        goto done;

diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index b97da39652d26dd205a2ac844bc6b8894bfcd4f9..0ee48c5ba764d1f7e9c943540138b953f80e9a33 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -325,7 +325,7 @@ ssize_t tmc_sg_table_get_data(struct tmc_sg_table *sg_table,
 static inline unsigned long
 tmc_sg_table_buf_size(struct tmc_sg_table *sg_table)
 {
-       return sg_table->data_pages.nr_pages << PAGE_SHIFT;
+       return (unsigned long)sg_table->data_pages.nr_pages << PAGE_SHIFT;
 }
 
 struct coresight_device *tmc_etr_get_catu_device(struct tmc_drvdata *drvdata);